The heat density of power devices and semiconductor packages has increased along with miniaturization and increased density of these devices. Electronic components installed in these devices thus require a technique that efficiently dissipates the generated heat of individual components to keep the components below the designed operating temperature. Fins that take advantage of convection, and heat conducting sheets that take advantage of heat conduction are commonly used as means to dissipate generated heat from individual components. However, with the sole use of the traditional approach using heat dissipating means such as above, it is difficult to keep a heat generating device below the designed operating temperature in a high heat-density environment.
Heat-dissipating coating materials and heat-dissipating sheets that take advantage of thermal radiation are available as resin compositions have attracted interest as a means to dissipate heat without requiring additional space. Among such resin compositions, heat-dissipating coating materials and heat-dissipating sheets with imparted thermal conductivity have considerably high heat dissipation with their ability to efficiently transfer the generated heat from a heat generating component on the inside and release the heat to the outside through the surface opposite the heat generating component.
FIG. 6 is a schematic cross sectional view of a resin composition produced by a traditional method. In order to prevent a heat spot due to heat generating portions of electronic devices and LED lights, a thermoplastic resin composition 18 is provided as a heat dissipating member by being installed on surfaces of these devices. For example, JP-A-2013-209508 describes a thermoplastic resin composition 18 that can be provided as a composition mixing a thermoplastic resin 15, a heat conductive filler 16, and a composite oxide 17.
However, in the thermoplastic resin composition 18 described in JP-A-2013-209508 (Patent Literature 1), the combined volume fraction of the heat conductive filler 16 and the composite oxide 17 with respect to the total volume of the thermoplastic resin 15 cannot be increased to 65 volume % or more for reasons related to moldability. Specifically, the thermoplastic resin composition 18 shown in Example 1 of Patent Literature 1 contains only 5 to 10 volume % of composite oxide 17 with respect to the total volume of the thermoplastic resin composition 18. The thermoplastic resin composition 18 shown in Patent Literature 1 is therefore probably insufficient in terms of dissipation of heat from the composition surface to outside.